This invention relates to carbonate polymer compositions containing additives which act as an ultra violet light stabilizers and heat stabilizers.
Carbonate polymers derived from reactions of dihydroxyorganic compounds, particularly the dihydric phenols, and carbonic acid derivatives such as phosgene, have found extensive commercial application because of their excellent physical properties. These thermoplastic polymers are suitable for the manufacture of molded parts wherein impact strength, rigidity, toughness, heat resistance and excellent electrical properties are required.
It is known from U.S. Pat. No. 3,367,958 that benzotriazoles are useful to stabilize polycarbonate resins against the effects of UV light. However, it has been found that these additives also degrade the resins during processing.
In view of the deficiencies of the conventional UV stabilized carbonate polymer compositions, it would be highly desirable to provide a carbonate polymer composition having resistance to UV light and which exhibits good molecular weight stability and optical stability upon processing.